PTL 1 discloses an expansion valve that includes an expansion unit configured to have a valve body which has a decompressing flow channel provided for decompressing a flowing fluid and which opens or closes the decompressing flow channel, and a diaphragm. The expansion valve disclosed in PTL 1 includes a temperature-sensing reactive member and an actuating bar, in addition to a power element serving as the expansion unit and the valve body. The temperature-sensing reactive member has a support portion which is in contact with the diaphragm and a temperature-sensing portion which axially extends from the support portion. An internal space which extends to the temperature-sensing portion is provided in the temperature-sensing reactive member. The support portion has a flange shape so as not to locally press the diaphragm. A communication hole is disposed in the diaphragm by causing a space inside the expansion unit and the internal space of the temperature-sensing reactive member to communicate with each other in order to enclose a refrigerant therein. The diaphragm and the temperature-sensing reactive member are hermetically joined to each other by means of welding.
The actuating bar is interposed between the temperature-sensing portion of the temperature-sensing reactive member and the valve body. The diaphragm expands, thereby transmitting displacement in the axial direction of the temperature-sensing reactive member to the valve body. That is, in the expansion valve disclosed in PTL 1, expansion of the expansion unit is transmitted from the diaphragm to the temperature-sensing reactive member, the actuating bar, and the valve body in this order.